Yes, there are red Belties. The most fabulous one ever was named Tabasco. He was a reserve champion but unfortunately contracted an incurable infection and had to be put down at an early age before he could be drawn/collected. He was from Four Winds Farm.
There are also several shades of dun. I have one , a silver dun, that at distance looks like a Charolais. I have two heifers that were as red as Bo until about one year when they turned brown. Also several shades of blonde, etc.
I think red are the scarcest, certainly less than 1% of registrations, possibly less than one in a thousand.